BJ Enterprises Sentry Tank Monitor is a self-contained unit designed to indicate a low or high tank level by sounding a 103-decibel siren. Engineered for use on most single- and double-walled above-ground tanks, the Sentry is primarily used by automotive and industrial markets to help prevent costly and unnecessary tank overflows or untimely inventory shortages, ideal for monitoring interstitial space as well. When activated to an alarm condition, the Sentry will sound its built-in siren for as long as it is connected to a power source, operating on AC power with a 12 volt transformer. A low-cost unit that is simple to install and easily maintained on-site, this unit also features weather-resitant housings for all its buttons, a UL buna sensor, and a 1/2" x 6' pipe that is easily field adjustable to provide a tank depth from 2" to 10'. The Sentry can not be used to run accessories.